Japan's new Defense Minister Shinjiro Koizumi said he is not ruling out "any options" to improve the country's military capabilities when asked about the plan of developing nuclear-powered submarines, as the United States ally faces threats from its neighbors.
Newsweek has emailed the Russian and Chinese foreign ministries for comment. North Korea's embassy in Beijing did not immediately respond to a request for comment.
Why It Matters
In its latest defense white paper, Japan's Defense Ministry said the country faces what it described as "the most severe and complex security environment" since World War II, citing military activities by Russia, China and North Korea across the western Pacific.
Japan has been reinforcing its counterstrike and standoff defense capabilities to strike enemy territory and defeat invading forces from beyond their defenses, including the purchase of long-range Tomahawk cruise missiles from the U.S., its closest treaty ally.
Last month, while calling for the development of advanced submarines, an expert panel of Japan's Defense Ministry said Tokyo should consider submarines powered by "next-generation" propulsion systems, a term widely seen as referring to nuclear reactors.
What To Know
During his first press conference as defense minister, Koizumi, who was appointed by Prime Minister Sanae Takaichi, said on October 22 that Tokyo would not exclude any options when considering measures to improve deterrence and response capabilities.
Without specifying nuclear power, Koizumi said next-generation power sources enable submarines to conduct "long-distance and long-term" submerged operations. All of Japan's operational submarines are conventionally powered, the defense outlet The War Zone reported.
While no decisions have been made regarding the use of next-generation submarine power sources, Koizumi said the development of submarines equipped with vertical launching system (VLS), is essential to strengthen Japan's standoff defense capabilities.
The VLS fires missiles vertically from the submarine, rather than horizontally through torpedo tubes. This design could increase U.S.-Japan naval interoperability, as almost all U.S. submarines are VLS-equipped, according to the defense outlet Naval News.
Japan's new government is formed by the Liberal Democratic Party and the Japan Innovation Party. Both parties agreed to consider acquiring VLS-equipped submarines armed with long-range missiles and featuring next-generation propulsion systems.
Russia, China and North Korea are expected to oppose Japan's plan to develop nuclear-powered submarines if it is realized, as they have urged Tokyo to commit to peaceful development and make what they called "a clean break" from World War II militarism.
What People Are Saying
Japan's Defense Minister Shinjiro Koizumi said at a press conference on October 22: "We would like to consider measures to improve our deterrence and response capabilities without ruling out any options, but we are not settling on any one option. At this point, we will consider the use of next-generation submarine power plants. Furthermore, I believe that enhancing Japan's deterrence and response capabilities can be interpreted in the context of this coalition agreement."
Japan's defense white paper 2025 commented: "Amid this security environment, the Ministry of Defense (MOD) and the Self-Defense Forces (SDF) are fundamentally reinforcing Japan’s defense capabilities with independence and initiative, in an effort to protect the lives and peaceful livelihoods of Japanese people and resolutely defend Japan's territorial land, waters, and airspace, as expressed in the three strategic documents."
What Happens Next
It remains unclear whether the U.S. will provide assistance if Japan decides to push forward with its nuclear-powered submarine program, as in the case of Australia, which is set to receive three U.S. submarines as part of its nuclear-powered fleet buildup.
